The present invention relates to an inductive charger coupling for charging batteries such as batteries of battery driven electric vehicles.
A prior art inductive charger coupling 100 for charging the batteries of battery driven electric vehicles is shown in FIGS. 13 to 15. The inductive charger coupling 100 includes a charging receptacle 100a and a flat charging paddle 100b. The receptacle 100a is electrically coupled to the battery (not shown) of the electric vehicle. The paddle 100b is electrically coupled to an external power supply (not shown).
The receptacle 100a includes a housing 110, a ferrite secondary core 120 and a flat secondary coil assembly 130. As shown in FIG. 15, the core 120 includes a right pillar 124a, a left pillar 124b, upper and lower bridge sections 126 and upper and lower inner supports 122. The cross sectional area of each pillar 124a, 124b is chosen to create a desired amount of magnetic flux during the charging operation of the battery. The upper bridge section 126 connects the upper end of the right pillar 124a and the upper end of the left pillar 124b. The lower bridge section 126 connects the lower end of the right pillar 124a and the lower end of the left pillar 124b. Each support 122 has a hollow cylindrical shape and is centrally arranged. The upper support 122 extends downward from the upper bridge section 126. The lower support 122 extends upward from the lower bridge section 126. The flat secondary coil assembly 130 surrounds and is attached to the lower support 122.
As shown in FIGS. 14 and 15, the paddle 100b includes a primary core 142 and a primary coil 140, which has a circular cross section. When the paddle 100b is plugged into the receptacle 100a, the primary core 142 is held between the upper and lower supports 122 of the secondary core 120, and the primary coil 140 is coaxially aligned with the secondary coil assembly 130 without contacting the secondary coil assembly 130. When alternating current is supplied to the primary coil 140 from the external power supply, magnetic flux is created by the primary coil 140. The magnetic flux forms a magnetic circuit, which extends around the secondary core 120, to induce an electromotive force in the secondary coil assembly 130 for generating electric current. The electric current is supplied to the battery through a cable and a rectifier (not shown) for charging.
As shown in FIG. 13, the core 120 of the prior art inductive charger coupling 100 extends straight across the distal arcuate end of the paddle 100b and has a width of 180 mm (as measured vertically in FIG. 13) The right pillar 124a and the left pillar 124b are located outside of the paddle 100b. Therefore, the housing 110 of the receptacle 100a must be relatively wide (200 mm) to accommodate the core 120.
The space available in vehicles is limited, so the relatively large receptacle 100a of the inductive charger coupling 100 is not suitable since the receptacle 100a of the inductive charger coupling 100 reduces the available space for other parts. The large receptacle causes crowding of other parts, which may lead to malfunctions due to radiated heat and other factors and makes maintenance difficult. Therefore, the large inductive charger coupling 100 is disadvantageous, especially, for compact cars.